Confinement of high-current steady-state ELMy H-modes with the JET Mark II divertor

This is the authors' abstract. We don't add key points for this paper.

The energy confinement time of high-current ELMy H-modes in JET is found to be lower than predicted by the scaling. An unprovoked transition to L-mode is often observed in ELMy H-modes without additional deuterium gas fuelling. This spontaneous H-L transition can be avoided by keeping the input power well above the L-H threshold power. The transition is analysed both in terms of global and local parameters.